1. Z. Kunszt et al., in: G. Altarelli, T. Sjöstrand, F. Zwirner (Eds.), Physics at LEP2, CERN 96-01, 1996, vol. 1, p. 141, hep-ph/9602352.
2. ALEPH Collaboration, Phys. Lett. B 401 (1997) 347;DELPHI Collaboration, Phys. Lett. B 397 (1997) 158;L3 Collaboration, Phys. Lett. B 398 (1997) 223;OPAL Collaboration, Phys. Lett. B 389 (1996) 416.
3. ALEPH Collaboration, contributed paper nr. 600 to EPS-HEP97; L3 Collaboration, CERN-PPE/97-98; OPAL Collaboration, CERN-PPE/97-116.
4. DELPHI Collaboration, contributed paper nr. 347 to EPS-HEP97.
5. D. Bardin et al., in: G. Altarelli, T. Sjöstrand, F. Zwirner (Eds.), Physics at LEP2, CERN 96-01, 1996, vol. 2, p. 3, hep-ph/9709270.